nixos: make several kernel common-config options optional

Realistically, common-config is useful, but there are a lot of things in
there that are non-optionally specified that aren't always useful. For
example, when deploying grsecurity, I don't want the bluetooth,
wireless, or input joystick/extra filesystem stack (XFS, etc), nor the
staging drivers tree.

The problem is that if you specify this in your own kernel config in the
grsecurity module, by saying 'BT n' to turn off bluetooth,
common-config turns on 'BT_HCIUART_BCSP y', which then becomes unused
and errors out.

This is really just an arbitrary picking at the moment, but it should be
OK.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
nixos: Fix sysctl option merging

Using pkgs.lib.mkOverride in a sysctl option would throw a bogus error.

Also, if you defined a sysctl multiple times in the same configuration,
only one of the values would be picked up, while the others were silently
discarded.

This patch should fix both issues. If you define a sysctl multiple
times at your highest defined priority level, you will get a proper
error with detailed location information.
glibc_multi: fix ldd on x86_64
glibc_multi: fix typo
keyutils: Update from 1.5.8 -> 1.5.9
ecryptfs: Update from 82 -> 104
Add SourceSansPro-1.050
Add SourceSerifPro-1.014
Adding Radicale package and service
Added package for kochi-substitute font.
Added kochi-substitute entry in all-packages.nix.
Added mirrors for sourceforge.jp.
Added license for kochi-substitute font.
Added maintainer for kochi-substitute.
Fix nixos-rebuild.sh to depend on Nix

And therefore always choose the correct architecture for the rebuilt
system regardless for the PATH setting of the user.
Revert "Fix configuring httpd with custom user/group."

This reverts commit 08f9da2e8eb9d3da39a1f28e191bd4fb7fd2fa45.
Fix configuring apache with extra user/group

This fix is consistent with all the other modules.
Fix trying to add users to non-existent groups
Removed non-free kochi-substitute and added kochi from Debian package.
Moved kochi-mincho and kochi-gothic back into one package.